1. Field of the Invention
The present invention relates to a method for discriminating a type of an optical recording media, and more particularly, to a method for discriminating types of optical recording mediums having different structures.
2. Description of the Background Art
Optical recording mediums, that is, optical disks, includes a ROM type for reading only, a WORM type capable of recording by one time, and a rewritable type disk capable of recording repeatedly.
The ROM type optical disk includes a compact disk read only memory (CD-ROM) and a digital versatile disk read only memory (DVD-ROM). The WORM type optical disk includes a recordable compact disk (CD-R) that is capable of recording by one time and a recordable digital disk (DVD-R) that is capable of recording by one time.
The disk capable of recording repeatedly includes rewritable compact disk (CD-RW) and a rewritable digital versatile disk (DVD-RW, DVD-RAM). Difference of the two is that in case of the DVD-RAM, data is recorded in both of a land and a groove, while, in case of the DVD-RW, data is recorded in the groove.
The various optical disks include a low reflection type disk and a high reflection type disk. Especially, the CD-R includes a metal group disk and a coloring group disk.
Meanwhile, a light source in use for an optical pick-up for DVD has a wave length of 635xcx9c650 nm (visible light, red color), and in order to read data from the CD-R, a light source having a wave length of 780 nm (infrared light) is required. In this respect, the data recorded in the CD-ROM can be read by the wave length of either 780 nm or 635xcx9c650 nm.
The DVD group disk has more compact recording density and shorter distance from the surface of the disk to the data recording face compared to the CD disk. The actual distance from the disk surface of the DVD disk to the data recording face is 0.6 mm, while that of the CD disk is 1.2 mm.
FIG. 1 is a schematic view showing a general construction of an optical recording/reproducing device which is capable of recording data in an optical disk and reproducing the recorded data therefrom.
As shown in the drawing, an optical pick-up 102 renders a light beam collected on an objective lens under the control of the servo controlling unit 106 to be placed on a signal track of an optical disk, collects again the light reflected on the signal recording face, and makes incident on an optical detector (not shown) to detect various signals.
The optical detector includes a plurality of optical detect devices. Electric signals in proportion to the quantity of light obtained by each optical detection device are outputted to an RF and servo error generation unit 104. The RF and servo error generation unit 104 detects an RF signal for reproducing a data, a focus error signal FE for servo-controlling or a tracking error signal TE from the electric signal outputted from the optical detector. The RF signal is outputted to a decoder 105 so as to be reproduced, and the servo error signal such as the FE and the TE are outputted to the servo controller 106. And, the control signal for recording a data is outputted to an encoder 103.
The encoder 103 encodes a data to be recorded to a recording pulse of a format as required by the optical disk 101 and records it in the optical disk 102 through the optical pick-up 102. The decoder 105 restores an original data from the RF signal.
A host such as a PC may be connected to the optical recording/reproducing device. The host transfers a recording/reproducing command through an interface 110 of the optical recording/reproducing device to a MICOM 111, transmits a data to be recorded to the encoder 103, and receives a reproduced data from the decoder 105. The MICOM 111 controls the encoder 103, the decoder 105 and the servo controlling unit 106 according to the recording/reproducing command.
As to the interface 110, an ATAPI (advanced technology attached packet interface) is typically used. The ATAPI refers to an interface standard between the optical recording/reproducing device such as a CD drive or a DVD drive and the host, which was proposed to transmit a data decoded in the optical recording/reproducing device to the host. The ATAPI serves to transmit the decoded data according to a protocol as defined in the host.
The servo controlling unit 106 processes the focus error signal FE and outputs a drive signal for focussing-controlling to a focus servo drive unit 107, and processes the tracking error signal TE and outputs a drive signal for tracking-controlling to a tracking servo drive unit 108. The focus servo drive unit 107 drives a focus actuator of the optical pick-up 102 to move the optical pick-up 102 upwardly and downwardly so that the optical disk 101 is rotated, tracing the up-down movement of the optical pick-up. That is, the focus actuator, which drives the objective lens collecting the light upwardly and downwardly, that is, in the focus axis direction, maintains evenly the distance between the objective lens and the optical disk 101 according to the focus control signal.
The tracking servo drive unit 108 drives the tracking actuator of the optical pick-up 102, according to which the objective lens of the optical pick-up 102 moves in the radial direction to the optical disk, thereby correcting a position of the light beam and following a predetermined track.
If the optical recording/reproducing device is a CD drive, what is needed is to discriminate a type of CD, that is, whether it is a high reflection disk or a low reflection disk. But, if it is the DVD drive (i.e., DVD-RAM system), it should be able to reproduce CD group disk as well as DVD group disk, considering that CD group software is vastly used.
Therefore, when the optical disk is inserted, it is necessary for the DVD drive to discriminate whether the inserted disk is the CD group disk or the DVD group disk, whether the discriminated disk in the same group is of a low reflection or a high reflection, or whether it is a reproducing-only type or a recordable type, so that the DVD drive can perform a suitable servo operation. Namely, without discriminating types of the disk, the servo wouldn""t be operated properly and it takes a long time to stabilize the servo operation. The reason for this is that servo error signal characteristics are different for disk types.
In this respect, since the RF level of the optical disk is different in terms of reflectivity, in the conventional art, whether it is a low reflection or a high reflection is judged by sensing the RF level. For example, in case of the DVD group disk, the size of the RF level is as follows: DVD-ROM greater than DVD-RW greater than DVD-RAM.
However, as to the method for discriminating types of disks of the conventional art, the reflectivity of the high reflection disk may be lowered down, and if it is actually lowered down for a cause, there is a high possibility that the lowered-down high reflection disk is misjudged as a low reflection disk.
In addition, since deflections are wide-ranged for disks, it may occur that there is no difference between RF levels of different disks. Especially, in case of the CD-R and the CR-ROM, since the both have a great reflectivity, it is not easy to set a threshold value for differentiating the two disks.
As described above, the method for discriminating types of disks by using the RF level of the conventional art has the problem in that an error may occur in differentiating disks, making it difficult to discriminate disks accurately. In addition, it takes a long time to stabilize the servo operation, degrading the performance of the system.
Therefore, an object of the present invention is to provide a method for discriminating a type of an optical recording medium which is capable of discriminating a DVD group disk and a CD group disk on the basis of a reference level of a focus search wave form.
Another object of the present invention is to provide a method for discriminating a type of an optical recording medium which is capable of discriminating a recordable disk and reproducing-only disk of the same group on the basis of a level of a focus error signal.
Still another object of the present invention is to provide a method for discriminating a type of an optical recording medium which is capable of discriminating a DVD-RAM and a DVD-RW of a DVD group on the basis of a level of a tracking error signal obtained by free running.
To achieve these and other advantages and in accordance with the purposed of the present invention, as embodied and broadly described herein, there is provided a method for discriminating a type of an optical recording medium including the steps of: identifying whether a disk is mounted; performing a focus-searching by rotating a mounted disk by means of a recording/reproducing system for a specific disk to detect a focus search level, and identifying whether the currently mounted disk belongs to a specific type on the basis of the detected focus-search level; and detecting an RF level and/or a focus error signal level by rotating the mounted disk, and identifying a type of the currently mounted disk on the basis of the detected signal.
In order to achieve the objects of the present invention, there is provided a method for judging a type of a disk to be currently recorded and reproduced among a plurality of disks of different physical characteristics, including the steps of: identifying whether a disk is mounted; performing a focus-searching by rotating a mounted disk by means of a recording/reproducing system for a specific disk to detect a focus search level, and identifying whether the currently mounted disk belongs to a specific type on the basis of the detected focus-search level; detecting an RF level and/or a focus error signal level by rotating the mounted disk, and identifying a type of the currently mounted disk on the basis of the detected signal.
In order to achieve the above objects, there is provided a method for performing a focus-searching to detect an RF signal and a focus error signal as an optical recording medium is inserted, and discriminating a type of an optical recording medium as inserted, including: a first discriminating step for detecting a focus zero cross position from a focus error signal as inputted during focus-searching, and discriminating whether the optical recording medium belongs to a CD group or to a DVD group by using a level of a focus search wave form detected from the focus zero cross position; and a second discriminating step for discriminating whether the optical recording medium discriminated as the CD group disk or the DVD group disk in the above step is a reproducing-only recording medium or a recordable recording medium by using an RF signal level or a focus error signal level.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, in the first discriminating step, a reference level is set for the focus search wave form, and the level of the detected focus search wave form is compared with the reference level, to thereby discriminate the CD group disk or the DVD group disk.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, if the level of the detected focus search wave form is higher than the pre-set reference level, the inserted optical recording medium is judged as the CD group disk, while if it is lower than the pre-set reference level, the inserted optical recording medium is judged as the DVD group disk.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, if no focus zero cross position is detected from the focus error signal, the inserted optical recording medium is judged as the CD group disk.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, in case that the inserted optical recording medium is discriminated as the CD group disk, CD-ROM, CD-R and CD-RW are discriminated on the basis of the level of the RF and the FE detected by using a light source of the DVD group disk in the second discriminating step.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, threshold values Vth1 and Vth2 (Vth1 greater than Vth2) are set for the RF levels detected for the CD-ROM, CD-R and CD-RW, on which if the detected RF level is greater than Vth1, the inserted optical recording medium is judged as the CD-ROM, if the detected RF level is smaller than Vth1 and greater than Vth2, it is judged as the CD-R, and if the detected RF level is smaller than Vth2, it is judged as the CD-RW.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, threshold values Vth3 and Vth4 (Vth3 greater than Vth4) are set for the FE levels detected for the CD-ROM, CD-R and CD-RW, on which if the detected FE level is greater than Vth3, the inserted optical recording medium is judged as the CD-ROM, if the detected FE LEVEL is smaller than Vth3 and greater than Vth4, it is judged as the CD-R, and if the detected FE level is smaller than Vth4, it is judged as the CD-RW.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, in case that the inserted optical recording medium is judged as the CD-R, a threshold value Vth5 is set for the RF level detected from the CD-R, on which if the detected RF level is greater than the threshold value, the inserted optical recording medium is judged to belong to a CD-R metal group, while if the detected RF level is below the threshold value, it is judged to belong to a CD-R coloring group.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, in case that the inserted optical recording medium is discriminated as the CD-R group disk, a threshold value Vth6 is set for the FE level detected from the CD-R, based on which if a detected FE level is higher than the threshold value, the inserted disk is judged as the CD-R metal group disk, while if the detected FE level is lower than the threshold value, the inserted disk is judged as the CD-R coloring group disk.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, in case that the inserted optical recording medium is discriminated as the DVD group disk in the first discriminating step, the DVD-ROM, DVD-R, DVD-RW and DVD-RAM are discriminated from the levels of the RF and FE detected by using a light source of DVD group disk.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, threshold values Vth1 and Vth2 are set for the RF levels detected for the DVD-ROM, DVD-R, DVD-RW and DVD-RAM, on which if a detected RF level is greater than Vth1, the inserted optical recording medium is judged as the DVD-ROM or the DVD-R, if a detected RF level is smaller than Vth1 and greater than Vth2, the inserted optical recording medium is judged as the DVD-RW, and if a detected RF level is smaller than Vth2, the inserted optical recording medium is judged as the DVD-RAM.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, threshold values Vth3 and Vth4 (Vth3 greater than Vth4) are set for FE levels detected for the DVD-ROM, DVD-R, DVD-RW and DVD-RAM, on which if a detected FE level is greater than Vth3, the inserted optical recording medium is judged as the DVD-ROM or the DVD-R, if a detected FE level is smaller than Vth3 and greater than Vth4, the inserted optical recording medium is judged as the DVD-RW, and if a detected FE level is smaller than Vth4, the inserted optical recording medium is judged as the DVD-RAM.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, in case that the inserted optical recording medium is judged as the DVD-ROM or the DVD-R, if there is a WBL, the inserted optical recording medium is judged as the DVD-R, while if there is no WBL, the inserted optical recording medium is judged as the DVD-ROM.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, when the optical recording medium inserted in the first discriminating step is discriminated as the DVD group disk, the DVD-ROM, the DVD-RW and the DVD-RAM are judged on the basis of the level of the tracking error signal obtained by free running.
According to the method for discriminating a type of an optical recording medium by detecting an RF signal and a focus error signal while performing a focus-searching as the optical recording medium is inserted in the present invention, threshold values Vth1 and Vth2 (Vth1 greater than Vth2) are set for tracking error levels detected for the DVD-ROM, DVD-RW and DVD-RAM, on which if a detected tracking error level is greater than Vth1, the inserted optical recording medium is judged as the DVD-RAM, if a detected tracking error level is smaller than Vth1 and greater than Vth2, the inserted optical recording medium is judged as the DVD-RW, and if a detected tracking error level is smaller than Vth2, the inserted optical recording medium is judged as the DVD-ROM.
These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modification within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.